1. Field of the Invention
The present invention relates to dish washers, and more particularly, to a dish washer can wash dishes with either an upper rack or lower rack inside of a wash chamber, and a device for controlling a washing water flow passage which makes the same available.
2. Background of the Related Art
The dish washer is an appliance in which detergent and washing water is sprayed onto dishes for automatic washing and drying the dish. FIG. 1 illustrates a related art dish washer.
Referring to FIG. 1, the related art dish washer is provided with a cabinet 1, a washing chamber 3, a plurality of racks 4 and 5, a cleaning filter 6, a sump 7, a pump 8, a plurality of arms 10 and 11, and a drain pump 12.
The cabinet 1 is an outside case of the dish washer. The cabinet 1 has a door 2 in one side, and the washing chamber 3 is provided to an inside of the cabinet 1.
The plurality of racks 4 and 5, for an example, an upper rack 4 and a lower rack 5 are provided to an inside of the washing chamber 3 for placing the dishes thereon. The cleaning filter 6 filters washing water from outside of the cabinet 1, the filtered washing water is gathered in the sump 7 and stored therein temporarily.
The pump 8 is, for an example, a centrifugal pump, for drawing the washing water from the sump 7 through a washing water inlet 8a and pumping out through a first outlet 8b and a second outlet 8c, respectively. The first outlet 8b and the second outlet 8c are connected to water passages that are lead to different parts of an inside of the washing chamber 3, such as the upper part and a lower part thereof. The water passage may be a connection pipe 9 connected between the upper part of the washing chamber 3 and the first outlet 8b. 
The plurality of arms 10 and 11, for an example, an upper arm 10 and a lower arm 11, are provided in the vicinity of racks 4 and 5 inside of the washing chamber 3. The arms 10 and 11 are rotatably connected to the connection pipe 9 and the second outlet 8c respectively, for being rotated and spraying water toward dishes on the racks 4 and 5. The drain pump 12 is provided for pumping the water, sprayed from the arms 10 and 11 and fallen down to a bottom of the washing chamber 3, to an outside of the dish water.
The foregoing related art dish washer washes the dishes by the following process.
Upon putting the dish washer into operation after placing the dishes on the racks 10 and 11 in the washing chamber 3 and closing the door 2, the washing water in the sump 7 is pumped as the pump 8 comes into operation. Of course, the washing water in the sump 7 is supplied from outside of the dish washer and filtered through the cleaning filter 6.
The washing water pumped by the pump 8 is discharged through the first outlet 8b and the second outlet 8c, wherein the washing water discharged to the first outlet 8b is supplied to the upper arm 10 via the connection pipe 9. The upper arm 10 is rotated, and sprays washing water, for washing the dishes on the upper rack 4.
On the other hand, the washing water, pumped by the pump 8 and discharged through the second outlet 8c, is supplied to the lower arm 11. The lower arm 11 is rotated and sprays washing water for washing the dishes on the lower rack 5.
The washing water having cleaned the dishes thus by above process falls down to a lower part of the washing chamber 3, and the drain pump 12 discharges the washing water to an exterior.
Of course, though the dish washer is provided with various sterilizing and drying devices for carrying out sterilizing and drying required after the washing, detailed description of which will be omitted.
In the meantime, the related art dish washer discharges the washing water pumped by the pump 8 to the first outlet 8b and the second outlet 8c, such that both the upper arm 10 and the lower arm 11 spray the washing water, simultaneously. However, such a structure has a problem in that much washing water is consumed unnecessarily even if the dishes are placed either on the upper rack 4 or on the lower rack 5 in the washing because there are a small amount of dishes to be washed.
Consequently, demands for a dish washer rises, which can wash the dishes on either the upper rack 4 or the lower rack 5, when the amount of dishes to be washed is small.